I. Internal Engine Components:
* Stroker Kit (Recommended): A 393 stroker kit (using a longer stroke crankshaft) is the most common and efficient way to get to 400hp. This increases displacement, providing a bigger foundation for power. You'll need appropriate connecting rods and pistons to match the stroke. Forged components are generally preferred for higher-output engines.
* High-Performance Cylinder Heads: Factory heads won't cut it for 400hp. You'll need aftermarket heads, such as Edelbrock RPM Performer heads, AFR (Air Flow Research) heads, or similar. These offer larger valves, better flow characteristics, and improved combustion chamber design. Consider the chamber volume to match your intended compression ratio.
* Camshaft: A performance camshaft is crucial. The specific cam profile will depend on your desired power band (low-end torque vs. high-rpm horsepower) and the other components. A custom grind from a reputable camshaft manufacturer is often the best approach to optimize performance.
* Pistons and Connecting Rods: As mentioned above, forged pistons and connecting rods are vital for handling the increased stress of higher horsepower. These should be chosen to complement the stroker kit and camshaft.
* Compression Ratio: A higher compression ratio (around 9.5:1 to 10.5:1, depending on fuel and camshaft) will increase power. However, this necessitates higher-octane fuel. A too-high compression ratio could lead to detonation without proper tuning and fuel.
* Crankshaft: A forged crankshaft is essential for a reliable high-horsepower build, especially with a stroker kit. This ensures sufficient strength to handle the increased forces.
II. Induction and Exhaust:
* Intake Manifold: An aftermarket performance intake manifold designed for your chosen heads and carburetion/fuel injection system is necessary. Examples include Edelbrock Performer RPM Air-Gap.
* Carburetor (or Fuel Injection): A large, high-flowing carburetor (e.g., a Holley 750 CFM or larger) or a fuel injection system (which offers better control and efficiency) is required to deliver the necessary fuel. A properly tuned fuel system is critical.
* Headers: Long-tube headers are essential for maximizing exhaust flow and power. These replace the restrictive factory manifolds.
* Exhaust System: A free-flowing exhaust system (with a proper diameter and minimal restrictions) is needed to complement the headers and allow exhaust gases to escape efficiently.
III. Other Considerations:
* Valvetrain: High-performance valve springs, retainers, and pushrods are necessary to handle the increased valve lift and rpm of the performance camshaft.
* Oil Pump and Pan: A high-volume oil pump ensures adequate lubrication under high RPM. An oil pan with baffles prevents oil starvation during hard cornering and acceleration.
* Ignition System: An upgraded ignition system (e.g., a MSD ignition) provides a stronger and more consistent spark, which improves combustion efficiency.
* Cooling System: A high-capacity radiator and electric fans might be necessary to manage the increased heat generated by a high-horsepower engine.
IV. Tuning:
* Professional Tuning: Proper tuning is absolutely critical. Whether you use a carburetor or fuel injection, professional tuning on a dyno is essential to optimize the air/fuel mixture, timing, and other parameters for maximum power and reliability. A poorly tuned engine can easily damage itself.
In Summary:
Building a 400hp 351 Windsor isn't a cheap undertaking. It requires careful planning, high-quality parts, and professional tuning. The cost can easily reach several thousand dollars, depending on the components and level of expertise used. Consult with engine builders and performance shops for guidance tailored to your specific needs and budget. They can help you select the right components and ensure a safe and reliable build.
